Real-image type optical finder
US5936775A · kind A · utility
23Cited by
6References
10Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jun 10, 1998 |
| Grant date | Aug 10, 1999 |
| Priority date | — |
| Expiry date | Jun 10, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B23/14
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In a real-image type optical finder, a positive first lens group (objective lens group), a positive second lens group (relay lens group and image erecting optical system), and a positive third lens group (eyepiece lens group), are included in that order from the object side. The optical system satisfies the following condition (1): EQU 5.0<L/f.sub.II <7.0; (1) wherein: L represents the distance between the surface closest to the object side on the first lens group and the surface closest to the user's eye side on the third lens group; and f.sub.II represents the focal length of the second lens group.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.